EP3581448B1 - A disc brake - Google Patents
A disc brake Download PDFInfo
- Publication number
- EP3581448B1 EP3581448B1 EP19169827.3A EP19169827A EP3581448B1 EP 3581448 B1 EP3581448 B1 EP 3581448B1 EP 19169827 A EP19169827 A EP 19169827A EP 3581448 B1 EP3581448 B1 EP 3581448B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- piston
- yoke
- actuation mechanism
- brake
- bearing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
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Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D65/00—Parts or details
- F16D65/38—Slack adjusters
- F16D65/40—Slack adjusters mechanical
- F16D65/52—Slack adjusters mechanical self-acting in one direction for adjusting excessive play
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D65/00—Parts or details
- F16D65/38—Slack adjusters
- F16D65/40—Slack adjusters mechanical
- F16D65/52—Slack adjusters mechanical self-acting in one direction for adjusting excessive play
- F16D65/56—Slack adjusters mechanical self-acting in one direction for adjusting excessive play with screw-thread and nut
- F16D65/567—Slack adjusters mechanical self-acting in one direction for adjusting excessive play with screw-thread and nut for mounting on a disc brake
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D55/00—Brakes with substantially-radial braking surfaces pressed together in axial direction, e.g. disc brakes
- F16D55/02—Brakes with substantially-radial braking surfaces pressed together in axial direction, e.g. disc brakes with axially-movable discs or pads pressed against axially-located rotating members
- F16D55/22—Brakes with substantially-radial braking surfaces pressed together in axial direction, e.g. disc brakes with axially-movable discs or pads pressed against axially-located rotating members by clamping an axially-located rotating disc between movable braking members, e.g. movable brake discs or brake pads
- F16D55/224—Brakes with substantially-radial braking surfaces pressed together in axial direction, e.g. disc brakes with axially-movable discs or pads pressed against axially-located rotating members by clamping an axially-located rotating disc between movable braking members, e.g. movable brake discs or brake pads with a common actuating member for the braking members
- F16D55/225—Brakes with substantially-radial braking surfaces pressed together in axial direction, e.g. disc brakes with axially-movable discs or pads pressed against axially-located rotating members by clamping an axially-located rotating disc between movable braking members, e.g. movable brake discs or brake pads with a common actuating member for the braking members the braking members being brake pads
- F16D55/2255—Brakes with substantially-radial braking surfaces pressed together in axial direction, e.g. disc brakes with axially-movable discs or pads pressed against axially-located rotating members by clamping an axially-located rotating disc between movable braking members, e.g. movable brake discs or brake pads with a common actuating member for the braking members the braking members being brake pads in which the common actuating member is pivoted
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D65/00—Parts or details
- F16D65/02—Braking members; Mounting thereof
- F16D65/04—Bands, shoes or pads; Pivots or supporting members therefor
- F16D65/092—Bands, shoes or pads; Pivots or supporting members therefor for axially-engaging brakes, e.g. disc brakes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D65/00—Parts or details
- F16D65/02—Braking members; Mounting thereof
- F16D65/12—Discs; Drums for disc brakes
- F16D65/123—Discs; Drums for disc brakes comprising an annular disc secured to a hub member; Discs characterised by means for mounting
- F16D65/124—Discs; Drums for disc brakes comprising an annular disc secured to a hub member; Discs characterised by means for mounting adapted for mounting on the wheel of a railway vehicle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D65/00—Parts or details
- F16D65/14—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D65/00—Parts or details
- F16D65/14—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position
- F16D65/16—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake
- F16D65/18—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake adapted for drawing members together, e.g. for disc brakes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D65/00—Parts or details
- F16D65/38—Slack adjusters
- F16D65/40—Slack adjusters mechanical
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D65/00—Parts or details
- F16D65/02—Braking members; Mounting thereof
- F16D2065/022—Rollers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2121/00—Type of actuator operation force
- F16D2121/02—Fluid pressure
- F16D2121/04—Fluid pressure acting on a piston-type actuator, e.g. for liquid pressure
Definitions
- the present invention relates to a disc brake. More particularly, but not exclusively, the present invention relates to an actuation mechanism for an air actuated disc brake, and a method of assembling a disc brake that includes the actuation mechanism.
- a yoke is included, a component that moves axially, to transmit force from an operating shaft of the brake to the piston, when the brake is actuated.
- the adjustment mechanism often has an input driving portion that is in communication with the operating shaft, so that when the gap between the friction material and the rotor is undesirably large, the operating shaft drives the driving portion, which then transmits a torque to the remainder of the adjustment mechanism, to cause the piston to extend and move the friction material towards the rotor.
- de-adjustment of the brake can occur, for example due to vibration-induced torques acting on the adjuster mechanism, causing the piston to extend or retract. This is undesirable as it can result in impairment of the brake function due to an excessively large or small pad to rotor air gap.
- Document DE102010011725A1 discloses a disk brake having a brake caliper and a brake actuation mechanism being supported in it.
- the actuation mechanism comprises:
- the rolling element bearing enables a precise control of friction within the actuation mechanism, helping to ensure that there is sufficient friction where it is needed, and potentially enabling the overall levels of friction to be generated within the wear adjustment mechanism to be reduced, which can, for example allow smaller and lighter components (e.g., a smaller wrap spring) to be used.
- the rolling element bearing also helps to locate the driving portion radially, helping to prevent misalignment of the driving portion.
- the yoke may comprise a generally inboard facing surface that opposes a generally outboard facing surface of the driving portion to define an annulus that locates the rolling element bearing.
- the surfaces of the yoke and the driving portion help to ensure accurate location of the rolling element bearing during assembly of the brake.
- the rolling element bearing may be a deep-groove ball bearing.
- a deep-groove ball bearing is able to accept radial and axial loads, and it has been found that the use of such a bearing within the actuation mechanism increases the controllability of required frictional contact between relevant components of the adjuster mechanism, to help ensure stable performance of the adjustment mechanism during the life of a disc brake and allows the yoke to reliably transit a return force to the piston when the braking load is removed.
- the yoke may comprise an inclined surface.
- the rolling element bearing may be an angular contact ball bearing.
- the angular contact bearing may have a corresponding inclined surface to engage the inclined surface of the yoke.
- An angular contact ball bearing is suitable for use with both radial and axial loads, so it particularly suited for this application.
- the engagement of the inclined surfaces helps to locate the bearing in the correct location.
- An inboard facing surface of the rotatable portion of the piston may engage an opposing outboard facing surface of the yoke such that friction is created between the inboard facing surface of the rotatable portion of piston and the outboard facing surface of yoke, to resist relative rotation of the yoke and the rotatable portion of the piston.
- This frictional contact helps to inhibit undesired vibration-induced torque from affecting the adjustment mechanism in operation, and causing undesired de-adjustment of the disc brake.
- a resilient element may be arranged to provide a load acting to urge the facing surfaces of the yoke and the piston into contact.
- the resilient element thereby generates a predetermined amount of friction between the surfaces so as to further control the undesired de-adjustment.
- the load from the resilient element helps maintain the coaxial alignment of the yoke and the piston during adjustment and or return of the piston.
- the driving portion may be part of a one-way clutch.
- the one-way clutch may further comprise a driven portion. Rotation of the yoke in relation to the rotatable portion of the piston may be frictionally resisted with a torque greater than the torque required to cause the one-way clutch to slip, when the actuation force is released at the end of a braking operation.
- One of the driven or driving portions of the one-way clutch may comprise an axially extending projecting portion.
- the other of the driven or driving portions may be rotatably mounted with respect to the projecting portion
- the resilient element may be arranged to apply a load to the projecting portion, the load being transmitted to the yoke via the rolling element bearing.
- the resilient element may be further arranged to apply a load to a torque limiting clutch of the adjustment mechanism.
- the resilient element may be further arranged to apply a load to the piston in an opposite direction to the load on the yoke.
- the adjustment mechanism may further comprise a stop mounted at an outboard end of the projecting portion to take the load from the resilient element.
- An outboard surface of the stop may be flush with an outboard surface of the projecting portion of the driving portion.
- the stop helps to set the level of pre-stress of the resilient element of the adjustment mechanism in the axial direction to help maintain alignment of the components, as well as to retain them. If the outboard surface of the stop is flush with the outboard surface of the projecting portion of the driving portion, it helps to ensure that the stop is mounted in the correct location during assembly of the adjustment mechanism.
- a second rolling element bearing may be located on a transmission path between the resilient element and the projecting portion, preferably wherein the first and second rolling element bearings are identical.
- the driving portion may be a drive drum.
- the driven portion may be a driven drum in communication with a wrap spring arranged to overlie and bridge the drive drum and driven drum.
- the drive drum may be directly engaged by a link member that is connected to, or integral with, the operating shaft.
- the rolling element bearing arrangement within the actuation mechanism enables the length of the wrap spring to be minimised.
- the friction clutch may comprise one or more input plates and one or more output plates arranged in a face-contacting relationship.
- the output plates may be located within the rotatable portion to directly drivingly engage the rotatable portion.
- the driven portion, the friction clutch and the clutch spring may be mounted on the projecting portion of the driving portion.
- the stop may have a bore. The stop may be mounted on the projecting portion of the driving portion.
- the piston may further comprise an outer portion restrained from rotating.
- the outer portion may be in threaded engagement with the rotatable portion.
- the yoke may comprise a sleeve portion projecting in an axially outboard direction.
- the rolling element bearing may be located between a circumferential surface of the sleeve portion of the yoke and a circumferential surface of the driving portion.
- the sleeve portion may be monolithically and integrally formed with the yoke.
- the rolling element bearing is located between a radially inner surface of the sleeve portion of the yoke and a radially outer surface of the driving portion.
- the adjustment mechanism may further comprise an annular spacer element located on the projecting portion of the driving portion, between an outboard facing surface of the driven portion and an inboard facing surface of the sleeve portion of the stop.
- An air gap may be defined between the spacer element and the driving portion.
- an air gap may be defined between the spacer element and the sleeve portion of the stop.
- the spacer element helps to ensure the components of the adjuster mechanism are generally located in the correct position, but allows for some axial play, to account for expansion or contraction of the components of the brake in use.
- the outboard facing surface of the yoke and the inboard facing surface of the rotatable portion of the piston may have different hardnesses.
- the outboard facing surface of the yoke or the inboard facing surface of the rotatable portion of the piston may be hardened during manufacture.
- a method of assembling a disc brake comprising the steps of: installing an actuation mechanism within the disc brake, the actuation mechanism comprising:
- a disc brake is also provided.
- the disc brake comprises the actuation mechanism of any of the above statements.
- the adjuster system comprises:
- the lubricant As the lubricant is inhibited from escaping from a defined location, it is restricted from migrating to other areas of the disc brake, reducing wear of the components of the adjustment mechanism, and extending the life of a disc brake comprising this adjuster system. If the lubricant is grease or a lubricating oil, a higher quantity of lubricant can be maintained near the parts of the wear adjustment mechanism needing lubrication, such as the wrap spring and/or friction clutch plates. Thus, should there be a degradation or escape of the lubricant over time, a greater amount of lubricant will nevertheless remain in contact with the parts requiring lubrication.
- the adjuster system may further comprise a stop mounted at an outboard end of the chamber to take the load from a resilient element of the adjuster mechanism.
- a sealing member may be arranged between the stop and a radially inner surface of the piston, to inhibit lubricant from migrating in an outboard direction at the outboard end of the piston.
- the arrangement of the adjuster system allows a sealing member to be arranged between the stop and a radially inner surface of the piston to inhibit fluid migration at the outboard end in a simple way to inhibit fluid migration.
- Figures 1 , 2 and 3 illustrate a disc brake 2 of the present invention.
- the disc brake incorporates an actuating mechanism comprising a single piston suitable for a commercial vehicle.
- This type of brake is particularly, but not exclusively, suitable for lighter duty heavy vehicles, for example smaller trucks, or a trailer of a tractor-trailer combination.
- the directions inboard and outboard refer to the typical orientation of the disc brake when fitted to a vehicle.
- the brake pad closest to the centre of the vehicle is the pad directly actuated by an actuation mechanism and being the inboard pad, and the outboard pad being one mounted to a bridge portion of the caliper.
- inboard can be equated with an actuating side of the disc brake, and outboard with a reaction side.
- the terms radial, circumferential, tangential and chordal describe orientations with respect to the brake rotor.
- the terms vertical and horizontal describe orientations with the disc brake mounted uppermost on an axle, whereas it will be appreciated that in use such a disc brake may adopt any axle orientation depending upon packaging requirements of the vehicle.
- the disc brake 2 comprises a caliper 3 having a housing 6 to accommodate the actuation mechanism and which is slideably mounted on a carrier 4 for movement in an inboard-outboard direction.
- the caliper 3 can slide on the carrier 4, by way of first and second guide pins 3a, 3b.
- first guide pin 3a is longer than the second guide pin 3b.
- An inboard brake pad 11a comprises a layer of friction material 13 and is arranged so that the friction material 13 faces a brake rotor 10 (also known as a brake disc).
- the inboard pad 11a is mounted to a brake pad support arrangement.
- the inboard brake pad support arrangement is a spreader plate 60, described in more detail below.
- the pad 11a is moveable in the direction of arrow 14 (see Figure 2 ) against the brake rotor 10 (example of rotor shown schematically in Figure 2 ).
- An outboard pad 11b also with a layer of friction material 13, is also provided.
- the outboard pad 11b is mounted to a further brake support arrangement.
- Suitable means are provided to urge an outboard brake pad 11b against the opposite side of the rotor 10.
- such means comprises a bridge 5 arranged so as to straddle the rotor 10 and to transmit the reaction force from an inboard operating shaft 21 to the outboard pad 11b.
- the housing 6 and bridge 5 are manufactured as a single monolithic casting, but in other embodiments, the bridge may be bolted or otherwise secured to the housing.
- the inboard and outboard brake pads 11a, 11b are mounted asymmetrically across an axis parallel to the brake rotor 10.
- the inboard pad 11a is mounted in a position that is laterally offset from the actuation mechanism, i.e. the line of action of the actuation mechanism does not pass through the mid-point of the inboard pad in a circumferential direction.
- the outboard pad 11b is mounted directly opposite the actuation mechanism, i.e. it is not laterally offset; the line of action of the actuation mechanism does pass through the mid-point of the outboard pad 11b in a circumferential direction when the pad 11b is mounted.
- the inboard and outboard brake pads 11a and 11b may not be laterally offset - i.e. may be aligned - or may be offset in another way.
- the inboard actuation mechanism comprises a single brake piston 15 (not shown on Figure 6 for clarity), slideable in the direction of arrow 14 (i.e. inboard-outboard) relative to the rotor 10 (not shown in Figure 5 , for clarity).
- the operating shaft 21 is pivoted about rollers 23 which are located along a transverse axis 28.
- rollers 23 which are spaced from one another laterally.
- Each roller 23 is located on a single bearing surface 27, each surface 27 being curved to accept the roller 23.
- Convex surfaces 21a of the operating shaft 21 are located opposite the roller 23.
- the operating shaft has an axis 22, being the radial centre of the arc defined by surfaces 21a, which is parallel and offset from the axis 28.
- the curved surface 21a locates in a semi-circular recess of a yoke 20.
- a surface 19 of the yoke 20 opposite the recess is in contact with an inboard end face of the piston 15.
- the operating shaft 21 further comprises a lever 24 having a pocket 25 adapted to receive an output push rod (not shown) of a brake actuator (e.g. an air chamber).
- the lever 24 is, in this embodiment, shaped as an inverted "U” (see Figures 4 and 10 in particular) and the line of action of the brake actuator (from pocket 25) is substantially over the line of action of the piston 15.
- needle roller bearings 20a Located between the curved surface 21a and the recess of the yoke 20, on either arm of the 'U' are needle roller bearings 20a, to enable the operating shaft 21 to pivot around the roller 23, in the recess of the yoke 20.
- another form of cam surface instead of the curved surface 21a of the operating shaft 21 may be employed (e.g. a plain bearing) and/or the arrangement may be reversed with the rollers 23 being in contact with the yoke 20, and the curved surface 21a being located in the recess of the caliper housing 6.
- the yoke 20 further includes a sleeve portion 40, which projects axially outboard from the yoke 20.
- the yoke 20 has a through bore extending axially through its centre, the bore also extending through the centre of the sleeve portion 40.
- the diameter of the bore at the sleeve portion 40 is lower than the diameter of bore for the remainder of the yoke, such that an internal shoulder 40a is defined between the sleeve portion 40 and the remainder of the yoke 20.
- the shoulder 40a defines an annular surface that faces in an inboard direction.
- the sleeve portion 40 and yoke 20 are made from a single piece of material, i.e. they are integrally and monolithically formed, but in alternative embodiments the sleeve portion 40 and yoke 20 are separate components that are fixed together during assembly, in any suitable way.
- a wear adjuster mechanism 30 to maintain a desired running clearance between the rotor 10 and pad 11a, 11b is described below.
- the operating shaft 21 is connected to a one-way clutch to transfer any rotation of the operating shaft beyond a predetermined degree.
- a link member Between the one-way clutch and operating shaft are a link member, which is driven by the operating shaft and drives the one-way clutch.
- the one-way clutch has a driving portion configured to rotate if the link member rotates, and a driven portion mounted on the driving portion, that is driven by the driving portion.
- the driving portion is a drive drum 35 with the driven portion being a driven drum 37.
- the link member is a pin that projects axially outboard from the operating shaft 21.
- the pin is in communication with a corresponding slot in the drive drum 35, the slot being at a position offset from the longitudinal axis of the drive drum 35 (which is aligned with the axis passing through the centre of the rotor of the brake), such that as the operating shaft pivots in use, the pin engages within the slot to cause the drive drum 35 to rotate (see Figure 7 for the slot within the drive drum).
- the slot is located on the operating shaft 21, and the pin on the drive drum 35.
- a gear arrangement could be used to ensure the operating shaft 21 is in driving communication with the drive drum 35.
- the drive drum 35 is made up of a collar portion 35a at its inboard end and an axially extending projecting portion 35b.
- the projecting portion is of a smaller diameter than the collar portion 35a, and extends outboard from the collar portion 35a, concentric with the piston 15.
- the projection portion is generally 'finger' shaped.
- a driven drum 37 located adjacent and outboard of the collar portion 35a of the drive drum 35, and concentric radially outward from the finger portion 35b of the drive drum 35, is a driven drum 37.
- the driven drum 37 acts as the driven portion of the one-way clutch and is mounted on the drive drum 35.
- the driven drum 37 comprises a plurality of axially extending recesses 38 which are arranged to accommodate corresponding lugs projecting radially inwardly from input plates 41a of a friction clutch 41.
- alternative arrangements for driving the clutch input plates are contemplated e.g. a different number of recesses, or projections rather than recesses.
- a wrap spring 39 is frictionally wrapped around outer circumferential surfaces of the collar portion 35a of the drive drum 35 and the driven drum 37, such that it bridges the two components and enables the two components to act as a one-way clutch.
- the wrap spring 39 can easily bridge the two components, as they are both cylindrical and have the same outer diameter at the location point where the wrap spring 39 engages.
- other suitable one-way clutches may be utilised, such as ball and ramp, or roller clutch/sprag clutch arrangements.
- the friction clutch 41 comprises output plates 41b positioned between the input plates 41a (see Figure 7 ).
- the output plates 41b of the clutch 41 have diametrically opposite radially outwardly facing lugs 43, which are not present on the input plates 41a.
- a ball and ramp arrangement could be used instead of a friction clutch with input and output plates, as is known in the art.
- a stop 44 projects radially inwardly from the inner piston 15b, radially outward of a circumferential shoulder portion 37a that projects radially outwardly from the driven drum 37.
- the shoulder portion 37a seats one end of the wrap spring 39.
- the wrap spring 39 is retained by the drive drum collar 35a and a washer 45a, but does have some axial freedom of movement.
- the drive drum 35 is restrained from moving in an outboard direction, and allowed to rotate relative to the yoke 20, by a first rolling element bearing 18a.
- the bearing 18a is an interference fit with the through bore of the yoke 20 and the drive drum 35.
- an outer race of the bearing 18a is rotationally fixed to the yoke, and an inner race of the bearing 18a is rotationally fixed to the drive drum 35.
- An inboard facing surface of the bearing 18a engages an outboard facing surface of a flange portion 35c at the inboard end of the drive drum 35.
- An outboard facing surface of the bearing 18a engages the annular inboard facing surface of the shoulder 40a of the sleeve portion 40 of the yoke 20. In this way, the drive drum 35 is restrained from moving axially outboard, once the brake is assembled.
- the bearing 18a is a deep-groove ball bearing, to help ensure that it will not fail under the axial loads that will be applied during operation of the brake.
- the bearing 18a also engages a radially outer surface of the collar 35a of the drive drum 35, to retain the drive drum 35 in a radial direction, and to accept radial loads passing through the drive drum 35.
- the bearing 18a also helps to locate the drive drum 35 radially, helping to prevent misalignment of the drive drum 35 within the adjustment mechanism, which can impair adjuster function during the life of the brake.
- the piston 15 comprises an outer piston 15a having an internal female thread, and an inner portion or inner piston 15b, having a complimentary external male thread. Therefore, in this embodiment the inner piston 15b is located within the outer piston 15a.
- the inner piston 15b has at least one recess in its inner surface. In this embodiment, the recesses are two longitudinally extending channels 42 located diametrically opposite one another. When the adjuster mechanism 30 is assembled, the lugs 43 of the output plates 41b of the clutch 41 locate within the channels 42, to key the output plates 41b to the inner piston 15b. Therefore, rotation of the output plates 41b results in rotation of the inner piston 15b.
- the sleeve portion 40 of the yoke 20 is located concentrically between the wrap spring 39 and the inner piston 15b.
- the sleeve portion 40 is restrained from rotating, as it is integral with, or secured to, the yoke 20, which is also configured to be non-rotatable when assembled in the disc brake.
- the inner piston 15b is configured to rotate during an adjustment operation, to cause the piston 15 to advance in the direction of the inboard brake pad 11a.
- An outboard facing surface of the yoke 20 opposes and contacts an inboard facing end surface of the inner piston 15b. Friction between these two surfaces helps to inhibit undesired vibration-induced torque from affecting the adjustment mechanism in operation, and causing undesired de-adjustment of the disc brake.
- the friction provides a consistent friction torque but in a small space envelope.
- the two opposing surfaces are preferably arranged to have sufficient friction to resist relative rotation of the yoke 20 and the inner portion 15b of the piston 15 with a torque greater than the torque required to cause the one-way clutch of the adjuster mechanism (in this case the wrap spring 39) to slip when the actuation force is released at the end of a braking operation. This helps to ensure that the one-way clutch slips rather than permits unwanted de-adjustment of the brake occurring during brake release.
- the outboard facing surface of the yoke of the piston is hardened.
- the inboard facing surface of the rotatable portion is hardened. It has been found that by hardening one of the two engaging surfaces, undesirable fretting corrosion can be significantly reduced.
- the wear adjuster mechanism 30 comprises first, second and third washers 45a, 45b, 45c.
- the first washer 45a is located adjacent and inboard of the friction clutch 41, and engages the friction clutch, as well as an outboard facing surface of the stop 44.
- the second washer 45b is located adjacent and outboard of the friction clutch 41, and an inboard surface of the washer 45b engages the friction clutch.
- An outboard face of the second washer 45b is acted on by a resilient element in the form, in this embodiment, of a compression spring 47.
- the compression spring 47 is arranged concentrically within the inner piston 15b, between the second washer 45b and the third washer 45c.
- the compression spring 47 acts as a clutch spring to load the friction clutch 41, to generate the required amount of friction to control the torque at which the friction clutch 41 slips.
- the compression spring 47 also controls the amount of friction between the outboard facing surface of the yoke and the inboard facing end surface of the inner piston 15b.
- a force transmission path is defined from the compression spring 47 to the inner piston 15b, to urge the inner piston 15b into axial engagement with the yoke 20, to resist relative rotation of the yoke 20 and the inner piston 15b. It will be appreciated that a spring is just one type of biasing element that could perform this function, and other biasing elements could also be used if desired.
- the compression spring 47 is pre-stressed by a stop 49 or end cap.
- the stop 49 is generally hat-shaped in cross-section, with a central bore so the stop 49 can be mounted on the projecting portion 35b of the drive drum 35.
- the stop 49 has a sleeve portion projecting in an axially inboard direction.
- a second rolling element bearing 18b is provided between a radially outer surface of the sleeve portion of the stop 49 and a radially inner surface of the inner piston 15b.
- the second rolling element bearing 18b is a thrust bearing that is arranged to isolate the compression spring 47 and output clutch plates 41b from the drive drum 35 in rotation.
- the stop 49 engages the third washer 45c via the thrust bearing to pre-stress the compression spring 47.
- a clearance exists between the cap and second bearing on the one hand, and the inner piston on the other.
- the second rolling element bearing is a ball bearing with radially arranged inner and outer races, the inner of which may be an interference fit with the stop 49 or directly in the projecting portion 35b so it may act itself as the stop.
- the compression spring 47 is compressed by and supported directly or indirectly on the outer race and is therefore isolated from rotation of the projecting portion 35b, but applies a force to the projecting portion and drive drum 35 as a whole in an outboard direction as in the embodiment above.
- the second bearing 18b is a standard ball bearing, but in alternative embodiments the second bearing 18b could be identical to the first rolling element bearing 18a, for example by also being a deep-groove ball bearing, or an angular contact ball bearing.
- the arrangement of the second bearing 18b also further assists to ensure radial alignment in an angular sense (i.e., the drive drum, the yoke and the inner piston and inner piston remain co-axial) under eccentric loads from the operating shaft during an adjustment operation, and in particular during the return of the operating shaft and piston to their brakes-off rest positions.
- the axial load from the compression spring 47 (of the order of 600N) is transmitted to the projecting portion 35b, the drive drum 35 and then into the yoke 20 by the first bearing 18a.
- the compression spring also loads the inner piston 15b via the friction clutch 41 in the opposite direction.
- the outboard surface of the stop 49 is flush with the outboard surface of the projecting portion 35b of the drive drum 35. This helps to ensure that the stop is mounted in the correct location during assembly of the adjustment mechanism.
- the stop 49 is mounted to the projecting portion 35b with an interference fit. It will be appreciated in other embodiments that the stop 49 could be mounted differently e.g., with circlips or the like.
- annular spacer element 51 Between an inboard facing surface of the sleeve portion of the stop 49 and an outboard facing surface of the driven drum 37 is an annular spacer element 51.
- the spacer element 51 is located on the projecting portion 35b of the drive drum 35.
- the spacer element 51 has some play in the axial direction. In other words, an air gap is defined between the spacer element 51 and the drive drum 35 and/or the spacer element 51 and the sleeve portion of the stop 49.
- the outer piston portion 15a is integral (i.e. formed monolithically from the same material by casting, or forging, for example) with the spreader plate 60.
- the spreader plate 60 locates the inboard brake pad 11a, as well as engages surfaces of the carrier 4. Therefore the interaction of the spreader plate 60 and carrier 4 prevent rotation of the outer piston 15a in use.
- the spreader plate 60 is smaller and/or may be a separate component, and an alternative anti-rotation feature is provided within the brake.
- the wear adjustment mechanism 30 is required to periodically advance the inboard brake pad 11a towards the rotor 10 to account for the loss of friction material 13, and to a lesser extent loss of material from the face of the rotor 10, due to wear.
- a predetermined amount of play or backlash is provided in the system between the pin and slot of the operating shaft and driving portion of the adjustment mechanism, (or between teeth of a gear based driving arrangement, or between the lugs of the input plates 41a of the clutch and the recesses 38, in other arrangements not shown in the figures).
- the play in the system means that no adjustment will occur.
- the aforesaid play is taken up. Whilst there is excess running clearance to be taken up, this rotation is transmitted via the drive drum 35 to the wrap spring 39, causing the wrap spring 39 to rotate around the drive drum 35 and driven drum 37 in a direction which causes the wrap spring 39 to tighten, transmitting the rotation from the drive drum 35 to the driven drum 37. More specifically, this rotation is transmitted as the wrap spring bridges the two components, i.e. a first end of the wrap spring 39 engages an outer surface of the drive drum 35 and a second end of the wrap spring 39 engages an outer surface of the driven drum 37.
- Rotation of the driven drum 37 causes rotation of the input plates 41a of the friction clutch 41, due to the interaction of the recesses 38 and the lugs of the input plates 41a.
- Rotation of the input plates 41a results in rotation of the output plates 41b, due to the friction between the input and output plates 41a, 41b.
- the lugs 43 of the output plates 41b engage the channels 42 of the inner piston 15b, the inner piston 15b is also caused to rotate.
- the engagement between the inboard-facing surface of the inner piston 15b and the outboard-facing surface of the yoke is configured to resist relative rotation of the yoke 20 and inner piston 15b with a torque greater than the torque required to cause the one-way clutch (in this case the wrap spring 39) to slip, when the actuation force is released at the end of a braking operation.
- This helps to ensure that the wrap spring 39 slips rather than permitting unwanted de-adjustment of the brake occurring during brake release.
- Uncontrolled unwinding of the wrap spring 39 is also minimised, which provides a more predictable, and hence controllable, friction level.
- the wear on the outer surfaces of the drums 35, 37 is also minimised.
- the arrangement also helps to remove uncertainties that may arise after manufacturing of the components, for example unpredictable tolerances, which may affect the function of the system.
- a chamber 70 is defined concentrically within the inner piston 15b and the outer piston 15a, for locating the adjuster mechanism 30 (see Figure 7 ).
- This actuation mechanism arrangement enables a simple arrangement to be provided for substantially sealing the chamber 70.
- the chamber 70 is substantially fluid-tight, so as to hold oil, or other suitable lubricating fluid for lubrication of the adjuster mechanism.
- a sealing member can be provided at location 72, to act between the stop 49 and the radially inner surface of the inner piston 15b.
- a sealing member can be provided at location 74, to act between the washer 45b and the radially inner surface of the inner piston 15b.
- This outboard sealing arrangement helps to ensure that lubricating fluid from the adjuster mechanism is inhibited in an outboard direction through the outboard end of the outer piston.
- the outboard sealing arrangement acts in combination with the spreader plate 60 and the outer piston 15a being integrally formed, which also helps to prevent loss of lubricating fluid from the chamber 70 in an outboard direction.
- a manual rewind apparatus incorporating an elongate manual rewind shaft is provided, to rewind the piston 15 back to its retracted position when it is necessary for the brake pads to be replaced, for example.
- a piston engaging end piece is mounted on the manual rewind shaft,
- the end piece can be generally circular in profile, but with two diametrically opposed projections.
- the end piece and the projections are dimensioned such that the projections locate within the longitudinally extending channels 42 of the inner piston 15b.
- the channels 42 allow the inner piston 15b to advance during a braking operation, whilst the shaft is axially fixed.
- the longitudinal channels 42 are arranged to be located away from the opposing 'twelve o'clock' and 'six o'clock' circumferential locations on the radially inner surface of the inner piston 15b, for example at 'three o'clock' and 'nine o'clock', when the brake is assembled on an axle of a vehicle.
- this helps to further inhabit passage of lubricant through the channels 42, which could occur under gravity through the most radially lower channel 42 (e.g. if a channel was at a 'six o'clock' position), when the brake is in a normal orientation.
- the chamber 70 comprises an opening at its inboard end, and loss of lubricating fluid in an inboard direction through the opening can be inhibited by a further sealing arrangement located at the inboard end within, or immediately adjacent, the chamber 70.
- a sealing member can be provided at location 76, between the outboard-facing surface of the bearing 18a and the inboard-facing surface of the shoulder 40a of the yoke 20.
- a sealing member can also be provided at location 78, between the radially outer surface of the collar 35a of the drive drum 35 and the radially inner surface of the yoke 20.
- a 'bath' of lubricating fluid is retained within the chamber 70, i.e. substantially no lubricant can pass inboard of the inboard sealing arrangement through a potential fluid transmission path defined between the yoke 20 and the drive drum 35. Similarly, no substantially no lubricant can pass outboard of the outboard sealing arrangement through a potential fluid transmission path defined between the inner piston 15b and the adjuster mechanism 30.
- the adjuster mechanism can be at least partially submerged in the 'bath' of the lubricating fluid. This reduces wear of the components of the adjuster mechanism, extending the life of a disc brake comprising this adjuster system.
- sealing members are preferably elastomeric o-rings, but it will be appreciated that any suitable sealing members could be used with minor modifications to the sealing arrangement that would be within the remit of the skilled person, e.g. lip seals, u-cups, metal sealing discs, etc.
- the chamber 70 is not fluid-tight, but simply configured to contain lubricant for lubrication of at least part of the wear adjustment mechanism, and inhibit lubricant from migrating away from the wear adjustment mechanism.
- the lubricant is inhibited from escaping from a defined location, it is restricted from migrating to other areas of the disc brake 2, reducing wear of the components of the adjustment mechanism, and extending the life of a disc brake 2 comprising this adjuster system.
- the lubricant is grease or a lubricating oil, a higher quantity of lubricant can be maintained near the parts of the wear adjustment mechanism needing lubrication, such as the wrap spring and/or friction clutch plates. Thus, should there be a degradation or escape of the lubricant over time, a greater amount of lubricant will nevertheless remain in contact with the parts requiring lubrication.
- One way to inhibit the lubricant is for the chamber and/or the wear adjustment mechanism to have a radial step arranged to define a barrier to inhibit the escape of lubricant in an inboard or outboard direction.
- the stop 44 of the inner piston 15b which projects radially inwardly could be dimensioned and arranged to inhibit any lubricant contained outboard of the stop 44 from escaping in an inboard direction past the stop 44.
- the washer 45a could also be dimensioned to extend radially to a sufficient extent to overlap and perform the same function, i.e. inhibit lubricant from escaping.
- a radial step tends to inhibit the escape of at least a portion of lubricant under gravity and may help to create a more tortuous path out of the chamber for lubricant in the event of lubricant being dislodged by virtue of the disc brake being subjected to vibration, jolts or the like.
- the radial step may advantageously extend around a complete circumference, such that a barrier exists irrespective of the orientation of the disc brake on a vehicle.
- the chamber and/or the wear adjustment mechanism may also have first and second opposed interface surfaces having a spacing sufficiently small therebetween so as to act a barrier to inhibit the escape of lubricant in an inboard or outboard direction.
- the washers 45a, 45b or 45c could be dimensioned to extend radially a sufficient extent to define only a small radial spacing between the two components, to inhibit lubricant from escaping.
- the sleeve portion 40 of the yoke 20 could extend further in the outboard direction, such that its radially inner surface opposes the radially outer surface of the shoulder portion 37a of the driven drum 37.
- First and second opposed interface surfaces further improve the containment of lubricant within the chamber.
- the surfaces may be radially opposed or axially opposed.
- the spacing required may be larger for relatively viscous lubricants such as grease, and a closer fit for thinner.
- the chamber 70 may be provided as a unitary item with the wear adjustment mechanism, such that removal of the adjustment mechanism from the caliper housing 6 of the disc brake 2 also results in removal of the chamber therefrom, for maintenance or replacement.
- the drive drum 135 is restrained from moving in an outboard direction, and allowed to rotate relative to the yoke 120, by a first rolling element bearing 118a.
- the first bearing 118a is an angular contact ball bearing.
- an inner chamfer is arranged between a radially inner facing surface of the first bearing 118a and an inboard facing surface of the first bearing 118a.
- An outer chamfer is arranged between a radially outer facing surface of the first bearing 118a and an outboard facing surface of the first bearing 118a.
- the inboard facing surface of the bearing 118a engages an outboard facing surface of a flange portion 135c at the inboard end of the drive drum 135.
- a surface inclined to the longitudinal axis of the drive drum 135 is defined by the outer chamfer of the first bearing 118a and engages a corresponding inclined surface of the shoulder 140a of the sleeve portion 140 of the yoke 120. In this way, the drive drum 35 is restrained from moving axially outboard, once the brake is assembled.
- the first bearing 118a is an angular contact ball bearing, it will perform well under the axial loads that will be applied during operation of the brake.
- the first bearing 118a also engages a radially outer surface of the collar 135a of the drive drum 135, to retain the drive drum 135 in a radial direction, and to accept radial loads passing through the drive drum 135. There is an axial clearance between the first bearing 118a and the wrap spring 139. As well as helping enable smooth rotation of the drive drum 135 relative to the yoke 120, the first bearing 118a also helps to locate the drive drum 135 radially, helping to prevent misalignment of the drive drum 135 within the adjustment mechanism, which can impair adjuster function during the life of the brake.
- Figure 9 shows a further alternative arrangement, with like reference numbers indicating like features, but with the prefix '2'.
- the sleeve portion 240 and yoke 220 are separate components that are not fixed together during assembly. Instead, in this embodiment, the sleeve portion 240 has an interference fit with the inner piston 215b.
- the sleeve portion 240 and inner piston 215b could be fixed together with any suitable arrangement that is within the knowledge of a person skilled in this field.
- the sleeve portion 240 has a reduced diameter portion at its inboard send that fits within the bore of the yoke 220.
- the sleeve portion 240 can rotate relative to the yoke 220.
- the diameter of the bore of the yoke at the sleeve portion 240 is lower than the diameter of bore for the remainder of the yoke, such that an internal shoulder 240a is defined between the sleeve portion 240 and the remainder of the yoke 220.
- the sleeve portion 240 projects axially outboard to a greater extent than the sleeve portion 40 of Figure 7 , such that it acts as a stop.
- the sleeve portion 240 is radially outward of the circumferential shoulder portion 237a that projects radially outwardly from the driven drum 237 and seats one end of the wrap spring 239.
- the wrap spring 239 is retained between the drive drum collar 235a and a washer 245a, but does have some axial freedom of movement.
- the sleeve portion 240 When the adjuster mechanism 230 is assembled, the sleeve portion 240 is located concentrically between the wrap spring 239 and the inner piston 215b. The sleeve portion 240 rotates with the inner piston 215b because of the interference fit.
- the inner piston 215b is configured to rotate during an adjustment operation, to cause the piston 215 to advance.
- An outboard facing surface of the yoke 220 opposes and contacts an inboard facing surface of the inner piston 215b. Friction between these two surfaces helps to inhibit undesired vibration-induced torque from affecting the adjustment mechanism in operation, and causing undesired de-adjustment of the disc brake.
- the friction provides a consistent friction torque but in a small space envelope.
- the two opposing surfaces are arranged to have sufficient friction to resist relative rotation of the yoke 220 and the inner portion 215b of the piston 215 with a torque greater than the torque required to cause the one-way clutch of the adjuster mechanism (in this case the wrap spring 239) to slip when the actuation force is released at the end of a braking operation. This helps to ensure that the one-way clutch slips rather than permits unwanted de-adjustment of the brake occurring during brake release.
- the radially outward facing surface of the sleeve is hardened.
- the radially inward facing surface of the rotatable portion is hardened. It has been found that by hardening one of the two engaging surfaces, undesirable fretting corrosion can be significantly reduced.
- the wear adjuster mechanism 230 comprises first and second washers 245a, 245b.
- the first washer 245a is located adjacent and inboard of the friction clutch 241, and engages the friction clutch, as well as an outboard facing surface of the sleeve portion 240.
- the second washer 245b is located adjacent and outboard of the friction clutch 241, and an inboard surface of the washer 245b engages the friction clutch 241.
- An outboard face of the second washer 245b is acted on by the compression spring 247.
- the compression spring 247 is, in this embodiment, arranged concentrically within the inner piston 215b, between the second washer 245b and the second bearing 218b to load the friction clutch 241.
- the compression spring 247 is pre-stressed by the second bearing 218b.
- the second rolling element bearing 218b is provided between a radially outer surface of the projecting portion 235b of the drive drum 235 and a radially inner surface of the inner piston 215b.
- the second rolling element bearing 218b is identical to the first rolling element bearing 218a, also being a deep-groove ball bearing, but is larger as it must fit between the drive drum 235 and inner piston 215b.
- the bearing 218b has radially arranged inner and outer races.
- the bearing 218b is axially fixed relative to the projecting portion 235b.
- the bearing 218b can slide relative to the inner piston 215b.
- the bearing 218b is axially fixed relative to the projecting portion 235b by the inner race being an interference fit with the projecting portion 235b.
- the compression spring 247 is compressed by and supported directly on the outer race and is therefore isolated from rotation of the projecting portion 235b, but applies a force to the drive drum 235 as a whole in an outboard direction because of the interference fit between the second bearing 218b and the projecting portion 235b of the drive drum 235.
- the inner piston 215b Due to the interference fit between the sleeve portion 240 and the inner piston 215b, the inner piston 215b is also urged in the inboard direction, towards the yoke 220. This helps to control the friction between the opposing surfaces of the yoke 220 and inner piston 215b and resist relative rotation of the two components, without the need for an inner piston stop, as required in previous embodiments.
- the axial location of the second bearing 218b is carefully controlled during assembly to apply an appropriate pre-load to the compression spring 247.
- the arrangement of the second bearing 218b also further assists with radial alignment in an angular sense (i.e. the drive drum, the yoke and the inner piston and inner piston remain co-axial) under eccentric loads from the operating shaft during an adjustment operation, and in particular during the return of the operating shaft and piston to their brakes-off rest positions.
- the axial load from the compression spring 247 (of the order of 600N) is transmitted to the drive drum 235 and then into the yoke 220 by the first bearing 218a.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Braking Arrangements (AREA)
Description
- The present invention relates to a disc brake. More particularly, but not exclusively, the present invention relates to an actuation mechanism for an air actuated disc brake, and a method of assembling a disc brake that includes the actuation mechanism.
- In many air disc brakes, for use on heavy vehicles such as trucks and buses, to actuate the brake and move brake pads closer to a rotor, a yoke is included, a component that moves axially, to transmit force from an operating shaft of the brake to the piston, when the brake is actuated.
- Many of these brakes also include adjustment mechanisms to set the position of the brake pads having friction material relative to the brake rotor, to account for wear of the friction material and the rotor in brake use. The adjustment mechanism often has an input driving portion that is in communication with the operating shaft, so that when the gap between the friction material and the rotor is undesirably large, the operating shaft drives the driving portion, which then transmits a torque to the remainder of the adjustment mechanism, to cause the piston to extend and move the friction material towards the rotor.
- However, in use, it can be difficult to ensure that this driving portion of the adjustment mechanism is correctly aligned within the disc brake during installation, and that it remains in this correct alignment during use. Misalignment can result in impairment of the function of the adjuster mechanism.
- Also, de-adjustment of the brake can occur, for example due to vibration-induced torques acting on the adjuster mechanism, causing the piston to extend or retract. This is undesirable as it can result in impairment of the brake function due to an excessively large or small pad to rotor air gap.
- It would be desirable to reduce the risk of misalignment of the driving portion of the adjuster mechanism and to reduce the risk of vibration-induced torques causing de-adjustment of the disc brake.
- Document
DE102010011725A1 discloses a disk brake having a brake caliper and a brake actuation mechanism being supported in it. - An actuation mechanism for a disc brake is provided. The actuation mechanism comprises:
- a non-rotatable yoke to transmit an actuating force from an operating shaft;
- a piston configured to be driven by the yoke to transmit the actuating force to a brake pad, the piston comprising a portion rotatable with respect to the yoke to cause the piston to extend; and
- a wear adjustment mechanism for adjusting extension of the piston to account for wear of the brake pad, the wear adjustment mechanism including a driving portion configured to be driven by the operating shaft, to transfer torque from the operating shaft to the rotatable portion of the piston to cause the rotatable portion to rotate and extend the piston,
- wherein a rolling element bearing is located between the driving portion of the adjustment mechanism and the yoke.
- As well as helping enable smooth rotation of the driving portion relative to the yoke, the rolling element bearing enables a precise control of friction within the actuation mechanism, helping to ensure that there is sufficient friction where it is needed, and potentially enabling the overall levels of friction to be generated within the wear adjustment mechanism to be reduced, which can, for example allow smaller and lighter components (e.g., a smaller wrap spring) to be used. The rolling element bearing also helps to locate the driving portion radially, helping to prevent misalignment of the driving portion.
- The yoke may comprise a generally inboard facing surface that opposes a generally outboard facing surface of the driving portion to define an annulus that locates the rolling element bearing.
- The surfaces of the yoke and the driving portion help to ensure accurate location of the rolling element bearing during assembly of the brake.
- The rolling element bearing may be a deep-groove ball bearing.
- A deep-groove ball bearing is able to accept radial and axial loads, and it has been found that the use of such a bearing within the actuation mechanism increases the controllability of required frictional contact between relevant components of the adjuster mechanism, to help ensure stable performance of the adjustment mechanism during the life of a disc brake and allows the yoke to reliably transit a return force to the piston when the braking load is removed.
- The yoke may comprise an inclined surface. Alternatively, the rolling element bearing may be an angular contact ball bearing. The angular contact bearing may have a corresponding inclined surface to engage the inclined surface of the yoke.
- An angular contact ball bearing is suitable for use with both radial and axial loads, so it particularly suited for this application. The engagement of the inclined surfaces helps to locate the bearing in the correct location.
- An inboard facing surface of the rotatable portion of the piston may engage an opposing outboard facing surface of the yoke such that friction is created between the inboard facing surface of the rotatable portion of piston and the outboard facing surface of yoke, to resist relative rotation of the yoke and the rotatable portion of the piston.
- This frictional contact helps to inhibit undesired vibration-induced torque from affecting the adjustment mechanism in operation, and causing undesired de-adjustment of the disc brake.
- A resilient element may be arranged to provide a load acting to urge the facing surfaces of the yoke and the piston into contact.
- The resilient element thereby generates a predetermined amount of friction between the surfaces so as to further control the undesired de-adjustment. In addition the load from the resilient element helps maintain the coaxial alignment of the yoke and the piston during adjustment and or return of the piston.
- The driving portion may be part of a one-way clutch. The one-way clutch may further comprise a driven portion. Rotation of the yoke in relation to the rotatable portion of the piston may be frictionally resisted with a torque greater than the torque required to cause the one-way clutch to slip, when the actuation force is released at the end of a braking operation.
- If the torque exceeds this level, the risk of unwanted de-adjustment is minimised.
- One of the driven or driving portions of the one-way clutch may comprise an axially extending projecting portion. The other of the driven or driving portions may be rotatably mounted with respect to the projecting portion
- Beneficially this provides a convenient and compact construction of the one-way clutch.
- The resilient element may be arranged to apply a load to the projecting portion, the load being transmitted to the yoke via the rolling element bearing.
- This enables the resilient element to be located conveniently within the mechanism.
- The resilient element may be further arranged to apply a load to a torque limiting clutch of the adjustment mechanism.
- Beneficially, this enables the resilient element to simultaneously perform a further function.
- The resilient element may be further arranged to apply a load to the piston in an opposite direction to the load on the yoke.
- Beneficially, this enables the resilient element to simultaneously perform a further function.
- The adjustment mechanism may further comprise a stop mounted at an outboard end of the projecting portion to take the load from the resilient element. An outboard surface of the stop may be flush with an outboard surface of the projecting portion of the driving portion.
- The stop helps to set the level of pre-stress of the resilient element of the adjustment mechanism in the axial direction to help maintain alignment of the components, as well as to retain them. If the outboard surface of the stop is flush with the outboard surface of the projecting portion of the driving portion, it helps to ensure that the stop is mounted in the correct location during assembly of the adjustment mechanism.
- A second rolling element bearing may be located on a transmission path between the resilient element and the projecting portion, preferably wherein the first and second rolling element bearings are identical.
- This rotationally isolates the resilient element from the projecting portion such that it does not influence the adjuster function in an unwanted manner. If the first and second bearings are identical, this minimises the parts inventory required to manufacture and service the mechanism.
- The driving portion may be a drive drum. The driven portion may be a driven drum in communication with a wrap spring arranged to overlie and bridge the drive drum and driven drum. During an adjustment operation, the drive drum may be directly engaged by a link member that is connected to, or integral with, the operating shaft.
- Advantageously, the rolling element bearing arrangement within the actuation mechanism enables the length of the wrap spring to be minimised.
- The friction clutch may comprise one or more input plates and one or more output plates arranged in a face-contacting relationship. The output plates may be located within the rotatable portion to directly drivingly engage the rotatable portion.
- The driven portion, the friction clutch and the clutch spring may be mounted on the projecting portion of the driving portion. The stop may have a bore. The stop may be mounted on the projecting portion of the driving portion.
- The piston may further comprise an outer portion restrained from rotating. The outer portion may be in threaded engagement with the rotatable portion.
- The yoke may comprise a sleeve portion projecting in an axially outboard direction. The rolling element bearing may be located between a circumferential surface of the sleeve portion of the yoke and a circumferential surface of the driving portion. The sleeve portion may be monolithically and integrally formed with the yoke.
- The rolling element bearing is located between a radially inner surface of the sleeve portion of the yoke and a radially outer surface of the driving portion.
- The adjustment mechanism may further comprise an annular spacer element located on the projecting portion of the driving portion, between an outboard facing surface of the driven portion and an inboard facing surface of the sleeve portion of the stop. An air gap may be defined between the spacer element and the driving portion. Alternatively, an air gap may be defined between the spacer element and the sleeve portion of the stop.
- The spacer element helps to ensure the components of the adjuster mechanism are generally located in the correct position, but allows for some axial play, to account for expansion or contraction of the components of the brake in use.
- The outboard facing surface of the yoke and the inboard facing surface of the rotatable portion of the piston may have different hardnesses. The outboard facing surface of the yoke or the inboard facing surface of the rotatable portion of the piston may be hardened during manufacture.
- It has been found that by having engaging surfaces of different hardnesses, e.g., by hardening one of the two engaging surfaces using any suitable process, fretting corrosion can be significantly reduced.
- A method of assembling a disc brake is also provided, comprising the steps of:
installing an actuation mechanism within the disc brake, the actuation mechanism comprising: - a non-rotatable yoke to transmit an actuating force from an operating shaft;
- a piston configured to be driven by the yoke to transmit the actuating force to a brake pad, the piston comprising a portion rotatable with respect to the yoke to cause the piston to extend; and
- a wear adjustment mechanism for adjusting extension of the piston to account for wear of the brake pad, the wear adjustment mechanism including a driving portion configured to be driven by the operating shaft, to transfer force from the operating shaft to the rotatable portion of the piston to cause the rotatable portion to rotate and extend the piston,
- wherein the method comprises the step of locating a rolling element bearing between the driving portion of the adjustment mechanism and the yoke.
- A disc brake is also provided. The disc brake comprises the actuation mechanism of any of the above statements.
- An adjuster system is also provided. The adjuster system comprises:
- a piston for applying an actuating force to a brake pad and being extensible to adjust the running clearance between a brake disc and the brake pad;
- a chamber; and
- a wear adjustment mechanism located within the chamber, for adjusting the extension of the piston,
- wherein the chamber is configured to contain lubricant for lubrication of at least part of the wear adjustment mechanism, and inhibit lubricant from migrating away from the at least part of the wear adjustment mechanism.
- As the lubricant is inhibited from escaping from a defined location, it is restricted from migrating to other areas of the disc brake, reducing wear of the components of the adjustment mechanism, and extending the life of a disc brake comprising this adjuster system. If the lubricant is grease or a lubricating oil, a higher quantity of lubricant can be maintained near the parts of the wear adjustment mechanism needing lubrication, such as the wrap spring and/or friction clutch plates. Thus, should there be a degradation or escape of the lubricant over time, a greater amount of lubricant will nevertheless remain in contact with the parts requiring lubrication.
- The adjuster system may further comprise a stop mounted at an outboard end of the chamber to take the load from a resilient element of the adjuster mechanism. A sealing member may be arranged between the stop and a radially inner surface of the piston, to inhibit lubricant from migrating in an outboard direction at the outboard end of the piston.
- The arrangement of the adjuster system allows a sealing member to be arranged between the stop and a radially inner surface of the piston to inhibit fluid migration at the outboard end in a simple way to inhibit fluid migration.
- Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
-
Figure 1 is an isometric view of a brake including inboard and outboard brake pads, according to an embodiment of the present invention; -
Figure 2 is a plan view of the brake offigure 1 , with a brake rotor in situ; -
Figure 3 is an isometric view of the brake offigure 1 from an inboard direction, with the inboard and outboard brake pads omitted for clarity; -
Figure 4 is an isometric view of the brake offigure 1 from an inboard direction, with the outboard brake pad and a caliper housing of the brake omitted for clarity; -
Figure 5 is an isometric view showing an adjuster arrangement of the brake offigure 1 , with the inboard brake pad included; -
Figure 6 is a cross-sectional view through an inboard-outboard radial plane 6-6 of the brake offigure 1 , with no brake pads or carrier included; -
Figure 7 is a cross-sectional view through an inboard-outboard horizontal plane of the actuator arrangement of a brake identical tofigure 1 , except with an alternative connection between the operating shaft and one-way clutch; -
Figure 8 is a cross-sectional view through an inboard-outboard horizontal plane of an alternative adjuster arrangement to the one shown in the brake offigure 1 ; and -
Figure 9 is a cross-sectional view through an inboard-outboard horizontal plane of a further alternative adjuster arrangement to the one shown in the brake offigure 1 . -
Figures 1 ,2 and3 illustrate adisc brake 2 of the present invention. The disc brake incorporates an actuating mechanism comprising a single piston suitable for a commercial vehicle. This type of brake is particularly, but not exclusively, suitable for lighter duty heavy vehicles, for example smaller trucks, or a trailer of a tractor-trailer combination. - Various orientations of the disc brake are described. In particular the directions inboard and outboard refer to the typical orientation of the disc brake when fitted to a vehicle. In this orientation the brake pad closest to the centre of the vehicle is the pad directly actuated by an actuation mechanism and being the inboard pad, and the outboard pad being one mounted to a bridge portion of the caliper. Thus inboard can be equated with an actuating side of the disc brake, and outboard with a reaction side. The terms radial, circumferential, tangential and chordal describe orientations with respect to the brake rotor. The terms vertical and horizontal describe orientations with the disc brake mounted uppermost on an axle, whereas it will be appreciated that in use such a disc brake may adopt any axle orientation depending upon packaging requirements of the vehicle.
- The
disc brake 2 comprises acaliper 3 having ahousing 6 to accommodate the actuation mechanism and which is slideably mounted on a carrier 4 for movement in an inboard-outboard direction. - As can be seen from the view in
Figure 4 with thehousing 6 omitted, thecaliper 3 can slide on the carrier 4, by way of first and second guide pins 3a, 3b. In this embodiment, thefirst guide pin 3a is longer than thesecond guide pin 3b. - An
inboard brake pad 11a comprises a layer offriction material 13 and is arranged so that thefriction material 13 faces a brake rotor 10 (also known as a brake disc). Theinboard pad 11a is mounted to a brake pad support arrangement. In this embodiment, the inboard brake pad support arrangement is aspreader plate 60, described in more detail below. Thepad 11a is moveable in the direction of arrow 14 (seeFigure 2 ) against the brake rotor 10 (example of rotor shown schematically inFigure 2 ). - An
outboard pad 11b, also with a layer offriction material 13, is also provided. Theoutboard pad 11b is mounted to a further brake support arrangement. Suitable means are provided to urge anoutboard brake pad 11b against the opposite side of therotor 10. In this embodiment, such means comprises abridge 5 arranged so as to straddle therotor 10 and to transmit the reaction force from aninboard operating shaft 21 to theoutboard pad 11b. In this embodiment thehousing 6 andbridge 5 are manufactured as a single monolithic casting, but in other embodiments, the bridge may be bolted or otherwise secured to the housing. In this embodiment, the inboard andoutboard brake pads brake rotor 10. Theinboard pad 11a is mounted in a position that is laterally offset from the actuation mechanism, i.e. the line of action of the actuation mechanism does not pass through the mid-point of the inboard pad in a circumferential direction. Theoutboard pad 11b is mounted directly opposite the actuation mechanism, i.e. it is not laterally offset; the line of action of the actuation mechanism does pass through the mid-point of theoutboard pad 11b in a circumferential direction when thepad 11b is mounted. In other embodiments the inboard andoutboard brake pads - With reference to the cut-away view of
Figure 5 and cross-section ofFigure 6 in particular, the inboard actuation mechanism comprises a single brake piston 15 (not shown onFigure 6 for clarity), slideable in the direction of arrow 14 (i.e. inboard-outboard) relative to the rotor 10 (not shown inFigure 5 , for clarity). - In order to urge the piston assembly in the direction of
arrow 14, the operatingshaft 21 is pivoted aboutrollers 23 which are located along atransverse axis 28. In this embodiment, there are tworollers 23, which are spaced from one another laterally. Eachroller 23 is located on asingle bearing surface 27, eachsurface 27 being curved to accept theroller 23. Convex surfaces 21a of the operatingshaft 21 are located opposite theroller 23. The operating shaft has anaxis 22, being the radial centre of the arc defined bysurfaces 21a, which is parallel and offset from theaxis 28. Thecurved surface 21a locates in a semi-circular recess of ayoke 20. Asurface 19 of theyoke 20 opposite the recess is in contact with an inboard end face of thepiston 15. The operatingshaft 21 further comprises alever 24 having apocket 25 adapted to receive an output push rod (not shown) of a brake actuator (e.g. an air chamber). Thelever 24 is, in this embodiment, shaped as an inverted "U" (seeFigures 4 and 10 in particular) and the line of action of the brake actuator (from pocket 25) is substantially over the line of action of thepiston 15. - Located between the
curved surface 21a and the recess of theyoke 20, on either arm of the 'U' areneedle roller bearings 20a, to enable the operatingshaft 21 to pivot around theroller 23, in the recess of theyoke 20. - In other embodiments, another form of cam surface instead of the
curved surface 21a of the operatingshaft 21 may be employed (e.g. a plain bearing) and/or the arrangement may be reversed with therollers 23 being in contact with theyoke 20, and thecurved surface 21a being located in the recess of thecaliper housing 6. - The
yoke 20 further includes asleeve portion 40, which projects axially outboard from theyoke 20. Theyoke 20 has a through bore extending axially through its centre, the bore also extending through the centre of thesleeve portion 40. The diameter of the bore at thesleeve portion 40 is lower than the diameter of bore for the remainder of the yoke, such that aninternal shoulder 40a is defined between thesleeve portion 40 and the remainder of theyoke 20. Theshoulder 40a defines an annular surface that faces in an inboard direction. - In this embodiment, the
sleeve portion 40 andyoke 20 are made from a single piece of material, i.e. they are integrally and monolithically formed, but in alternative embodiments thesleeve portion 40 andyoke 20 are separate components that are fixed together during assembly, in any suitable way. - Application of a force in the direction of arrow 26 (
Figure 5 ) causes pivoting movement of the operatingshaft 21 about therollers 23 and thecurved surface 21a bears on theyoke 20. The offset axes 28 and 22 cause theyoke 20 to move in the direction of thepiston 15, contacting thepiston 15 and causing thepiston 15 to urge thefriction material 13 of thebrake pad 11a directly against therotor 10. A reaction force from the operatingshaft 21 is transmitted to the bearingsurface 27 of thecaliper 3 via therollers 23 and is then transmitted to theoutboard pad 11b via thebridge 5, with thefriction material 13 of theoutboard pad 11b being urged against therotor 10, such that thepads - A
wear adjuster mechanism 30 to maintain a desired running clearance between therotor 10 andpad shaft 21 is connected to a one-way clutch to transfer any rotation of the operating shaft beyond a predetermined degree. Between the one-way clutch and operating shaft are a link member, which is driven by the operating shaft and drives the one-way clutch. The one-way clutch has a driving portion configured to rotate if the link member rotates, and a driven portion mounted on the driving portion, that is driven by the driving portion. In this embodiment, the driving portion is adrive drum 35 with the driven portion being a drivendrum 37. The link member is a pin that projects axially outboard from the operatingshaft 21. The pin is in communication with a corresponding slot in thedrive drum 35, the slot being at a position offset from the longitudinal axis of the drive drum 35 (which is aligned with the axis passing through the centre of the rotor of the brake), such that as the operating shaft pivots in use, the pin engages within the slot to cause thedrive drum 35 to rotate (seeFigure 7 for the slot within the drive drum). In an alternative embodiment, the slot is located on the operatingshaft 21, and the pin on thedrive drum 35. In a further alternative, a gear arrangement could be used to ensure the operatingshaft 21 is in driving communication with thedrive drum 35. - The
drive drum 35 is made up of acollar portion 35a at its inboard end and an axially extending projectingportion 35b. In this embodiment, the projecting portion is of a smaller diameter than thecollar portion 35a, and extends outboard from thecollar portion 35a, concentric with thepiston 15. In other words, the projection portion is generally 'finger' shaped. In this embodiment, located adjacent and outboard of thecollar portion 35a of thedrive drum 35, and concentric radially outward from thefinger portion 35b of thedrive drum 35, is a drivendrum 37. - The driven
drum 37 acts as the driven portion of the one-way clutch and is mounted on thedrive drum 35. The drivendrum 37 comprises a plurality of axially extendingrecesses 38 which are arranged to accommodate corresponding lugs projecting radially inwardly frominput plates 41a of afriction clutch 41. In other embodiments alternative arrangements for driving the clutch input plates are contemplated e.g. a different number of recesses, or projections rather than recesses. - A
wrap spring 39 is frictionally wrapped around outer circumferential surfaces of thecollar portion 35a of thedrive drum 35 and the drivendrum 37, such that it bridges the two components and enables the two components to act as a one-way clutch. Thewrap spring 39 can easily bridge the two components, as they are both cylindrical and have the same outer diameter at the location point where thewrap spring 39 engages. In other embodiments other suitable one-way clutches may be utilised, such as ball and ramp, or roller clutch/sprag clutch arrangements. - The
friction clutch 41 comprisesoutput plates 41b positioned between theinput plates 41a (seeFigure 7 ). Theoutput plates 41b of the clutch 41 have diametrically opposite radially outwardly facinglugs 43, which are not present on theinput plates 41a. Alternatively a ball and ramp arrangement could be used instead of a friction clutch with input and output plates, as is known in the art. - A
stop 44 projects radially inwardly from theinner piston 15b, radially outward of acircumferential shoulder portion 37a that projects radially outwardly from the drivendrum 37. Theshoulder portion 37a seats one end of thewrap spring 39. In the axial direction, thewrap spring 39 is retained by thedrive drum collar 35a and awasher 45a, but does have some axial freedom of movement. - As can be seen most clearly from
Figure 7 , thedrive drum 35 is restrained from moving in an outboard direction, and allowed to rotate relative to theyoke 20, by a first rolling element bearing 18a. Thebearing 18a is an interference fit with the through bore of theyoke 20 and thedrive drum 35. In other words, an outer race of thebearing 18a is rotationally fixed to the yoke, and an inner race of thebearing 18a is rotationally fixed to thedrive drum 35. - An inboard facing surface of the
bearing 18a engages an outboard facing surface of aflange portion 35c at the inboard end of thedrive drum 35. An outboard facing surface of thebearing 18a engages the annular inboard facing surface of theshoulder 40a of thesleeve portion 40 of theyoke 20. In this way, thedrive drum 35 is restrained from moving axially outboard, once the brake is assembled. - In this embodiment, the
bearing 18a is a deep-groove ball bearing, to help ensure that it will not fail under the axial loads that will be applied during operation of the brake. Thebearing 18a also engages a radially outer surface of thecollar 35a of thedrive drum 35, to retain thedrive drum 35 in a radial direction, and to accept radial loads passing through thedrive drum 35. There is an axial clearance between thebearing 18a and thewrap spring 39. As well as helping enable smooth rotation of thedrive drum 35 relative to theyoke 20, thebearing 18a also helps to locate thedrive drum 35 radially, helping to prevent misalignment of thedrive drum 35 within the adjustment mechanism, which can impair adjuster function during the life of the brake. - The
piston 15 comprises anouter piston 15a having an internal female thread, and an inner portion orinner piston 15b, having a complimentary external male thread. Therefore, in this embodiment theinner piston 15b is located within theouter piston 15a. Theinner piston 15b has at least one recess in its inner surface. In this embodiment, the recesses are two longitudinally extendingchannels 42 located diametrically opposite one another. When theadjuster mechanism 30 is assembled, thelugs 43 of theoutput plates 41b of the clutch 41 locate within thechannels 42, to key theoutput plates 41b to theinner piston 15b. Therefore, rotation of theoutput plates 41b results in rotation of theinner piston 15b. - The components above, that are located between the operating shaft and inner and outer piston, define a transmission path of the
wear adjuster mechanism 30. - When the
adjuster mechanism 30 is assembled, thesleeve portion 40 of theyoke 20 is located concentrically between thewrap spring 39 and theinner piston 15b. Thesleeve portion 40 is restrained from rotating, as it is integral with, or secured to, theyoke 20, which is also configured to be non-rotatable when assembled in the disc brake. However, theinner piston 15b is configured to rotate during an adjustment operation, to cause thepiston 15 to advance in the direction of theinboard brake pad 11a. An outboard facing surface of theyoke 20 opposes and contacts an inboard facing end surface of theinner piston 15b. Friction between these two surfaces helps to inhibit undesired vibration-induced torque from affecting the adjustment mechanism in operation, and causing undesired de-adjustment of the disc brake. Advantageously, the friction provides a consistent friction torque but in a small space envelope. - The two opposing surfaces are preferably arranged to have sufficient friction to resist relative rotation of the
yoke 20 and theinner portion 15b of thepiston 15 with a torque greater than the torque required to cause the one-way clutch of the adjuster mechanism (in this case the wrap spring 39) to slip when the actuation force is released at the end of a braking operation. This helps to ensure that the one-way clutch slips rather than permits unwanted de-adjustment of the brake occurring during brake release. In this embodiment, the outboard facing surface of the yoke of the piston is hardened. In alternative embodiments, the inboard facing surface of the rotatable portion is hardened. It has been found that by hardening one of the two engaging surfaces, undesirable fretting corrosion can be significantly reduced. - The
wear adjuster mechanism 30 comprises first, second andthird washers first washer 45a is located adjacent and inboard of thefriction clutch 41, and engages the friction clutch, as well as an outboard facing surface of thestop 44. Thesecond washer 45b is located adjacent and outboard of thefriction clutch 41, and an inboard surface of thewasher 45b engages the friction clutch. An outboard face of thesecond washer 45b is acted on by a resilient element in the form, in this embodiment, of acompression spring 47. Thecompression spring 47 is arranged concentrically within theinner piston 15b, between thesecond washer 45b and thethird washer 45c. Thecompression spring 47 acts as a clutch spring to load thefriction clutch 41, to generate the required amount of friction to control the torque at which the friction clutch 41 slips. - The
compression spring 47 also controls the amount of friction between the outboard facing surface of the yoke and the inboard facing end surface of theinner piston 15b. A force transmission path is defined from thecompression spring 47 to theinner piston 15b, to urge theinner piston 15b into axial engagement with theyoke 20, to resist relative rotation of theyoke 20 and theinner piston 15b. It will be appreciated that a spring is just one type of biasing element that could perform this function, and other biasing elements could also be used if desired. - The
compression spring 47 is pre-stressed by astop 49 or end cap. In this embodiment, thestop 49 is generally hat-shaped in cross-section, with a central bore so thestop 49 can be mounted on the projectingportion 35b of thedrive drum 35. Thestop 49 has a sleeve portion projecting in an axially inboard direction. A second rolling element bearing 18b is provided between a radially outer surface of the sleeve portion of thestop 49 and a radially inner surface of theinner piston 15b. In this embodiment the second rolling element bearing 18b is a thrust bearing that is arranged to isolate thecompression spring 47 and outputclutch plates 41b from thedrive drum 35 in rotation. Thestop 49 engages thethird washer 45c via the thrust bearing to pre-stress thecompression spring 47. A clearance exists between the cap and second bearing on the one hand, and the inner piston on the other. - In an alternative embodiment (not shown), the second rolling element bearing is a ball bearing with radially arranged inner and outer races, the inner of which may be an interference fit with the
stop 49 or directly in the projectingportion 35b so it may act itself as the stop. Thecompression spring 47 is compressed by and supported directly or indirectly on the outer race and is therefore isolated from rotation of the projectingportion 35b, but applies a force to the projecting portion and drivedrum 35 as a whole in an outboard direction as in the embodiment above. - In this embodiment, the
second bearing 18b is a standard ball bearing, but in alternative embodiments thesecond bearing 18b could be identical to the first rolling element bearing 18a, for example by also being a deep-groove ball bearing, or an angular contact ball bearing. - In both embodiments, the arrangement of the
second bearing 18b also further assists to ensure radial alignment in an angular sense (i.e., the drive drum, the yoke and the inner piston and inner piston remain co-axial) under eccentric loads from the operating shaft during an adjustment operation, and in particular during the return of the operating shaft and piston to their brakes-off rest positions. The axial load from the compression spring 47 (of the order of 600N) is transmitted to the projectingportion 35b, thedrive drum 35 and then into theyoke 20 by thefirst bearing 18a. The compression spring also loads theinner piston 15b via the friction clutch 41 in the opposite direction. As such, even when the return springs 46 act on theyoke 20 and this in turn "pulls" thepiston 15 back, the compression spring load maintains full face contact between the yoke and theinner piston 15b and with it the axial alignment of the components. - In this embodiment, the outboard surface of the
stop 49 is flush with the outboard surface of the projectingportion 35b of thedrive drum 35. This helps to ensure that the stop is mounted in the correct location during assembly of the adjustment mechanism. Thestop 49 is mounted to the projectingportion 35b with an interference fit. It will be appreciated in other embodiments that thestop 49 could be mounted differently e.g., with circlips or the like. - Between an inboard facing surface of the sleeve portion of the
stop 49 and an outboard facing surface of the drivendrum 37 is anannular spacer element 51. Thespacer element 51 is located on the projectingportion 35b of thedrive drum 35. In this embodiment, thespacer element 51 has some play in the axial direction. In other words, an air gap is defined between thespacer element 51 and thedrive drum 35 and/or thespacer element 51 and the sleeve portion of thestop 49. - In this embodiment, the
outer piston portion 15a is integral (i.e. formed monolithically from the same material by casting, or forging, for example) with thespreader plate 60. Thespreader plate 60 locates theinboard brake pad 11a, as well as engages surfaces of the carrier 4. Therefore the interaction of thespreader plate 60 and carrier 4 prevent rotation of theouter piston 15a in use. In alternative embodiments, thespreader plate 60 is smaller and/or may be a separate component, and an alternative anti-rotation feature is provided within the brake. - In order to maintain a desired running clearance between the brake pads and rotor, the
wear adjustment mechanism 30 is required to periodically advance theinboard brake pad 11a towards therotor 10 to account for the loss offriction material 13, and to a lesser extent loss of material from the face of therotor 10, due to wear. - A predetermined amount of play or backlash is provided in the system between the pin and slot of the operating shaft and driving portion of the adjustment mechanism, (or between teeth of a gear based driving arrangement, or between the lugs of the
input plates 41a of the clutch and therecesses 38, in other arrangements not shown in the figures). In a normal braking operation in which the running clearance is within the desired parameters, as the operatingshaft 21 pivots, the play in the system means that no adjustment will occur. - If the running clearance is however greater than the desired range, the aforesaid play is taken up. Whilst there is excess running clearance to be taken up, this rotation is transmitted via the
drive drum 35 to thewrap spring 39, causing thewrap spring 39 to rotate around thedrive drum 35 and drivendrum 37 in a direction which causes thewrap spring 39 to tighten, transmitting the rotation from thedrive drum 35 to the drivendrum 37. More specifically, this rotation is transmitted as the wrap spring bridges the two components, i.e. a first end of thewrap spring 39 engages an outer surface of thedrive drum 35 and a second end of thewrap spring 39 engages an outer surface of the drivendrum 37. Rotation of the drivendrum 37 causes rotation of theinput plates 41a of thefriction clutch 41, due to the interaction of therecesses 38 and the lugs of theinput plates 41a. Rotation of theinput plates 41a results in rotation of theoutput plates 41b, due to the friction between the input andoutput plates lugs 43 of theoutput plates 41b engage thechannels 42 of theinner piston 15b, theinner piston 15b is also caused to rotate. - Since the
outer piston 15a is restrained from rotation by the engagement of thespreader plate 60 and the carrier 4, this causes a lengthening of thepiston 15 to reduce the running clearance. At the point at which thefriction material 13 comes into full contact with therotor 10, the torque passing through the adjustment mechanism will start to increase. When this torque increases to a level that is higher than the maximum torque value of thefriction clutch 41, the friction clutch 41 slips and further extension of theouter piston 15a is prevented. Once the braking operation ceases, return springs 46 act to urge the operatingshaft 21 back to its rest position. A corresponding retraction of theinner piston 15b is prevented since thewrap spring 39 relaxes and does not transmit a reverse rotation to the drivendrum 37. - Preferably, the engagement between the inboard-facing surface of the
inner piston 15b and the outboard-facing surface of the yoke is configured to resist relative rotation of theyoke 20 andinner piston 15b with a torque greater than the torque required to cause the one-way clutch (in this case the wrap spring 39) to slip, when the actuation force is released at the end of a braking operation. This helps to ensure that thewrap spring 39 slips rather than permitting unwanted de-adjustment of the brake occurring during brake release. - The co-axial mounting of the
adjuster mechanism 30 within thepiston 15 minimises the space required by the mechanism within the housing, resulting in a lighter, more compact housing. - As the
wrap spring 39 directly engages the outer surface of thedrive drum 35 and the drivendrum 37, any potential backlash that may occur between thedrive drum 35 and thewrap spring 39, or the drivendrum 37 and thewrap spring 39, is minimised, which can help to reduce wear of the components. Uncontrolled unwinding of thewrap spring 39 is also minimised, which provides a more predictable, and hence controllable, friction level. The wear on the outer surfaces of thedrums - As described above, the components of the
adjuster mechanism 30 are contained within thepiston 15, i.e. achamber 70 is defined concentrically within theinner piston 15b and theouter piston 15a, for locating the adjuster mechanism 30 (seeFigure 7 ). - This actuation mechanism arrangement enables a simple arrangement to be provided for substantially sealing the
chamber 70. Thechamber 70 is substantially fluid-tight, so as to hold oil, or other suitable lubricating fluid for lubrication of the adjuster mechanism. - At the outboard end, a sealing member can be provided at
location 72, to act between thestop 49 and the radially inner surface of theinner piston 15b. Alternatively, a sealing member can be provided atlocation 74, to act between thewasher 45b and the radially inner surface of theinner piston 15b. - This outboard sealing arrangement helps to ensure that lubricating fluid from the adjuster mechanism is inhibited in an outboard direction through the outboard end of the outer piston. The outboard sealing arrangement acts in combination with the
spreader plate 60 and theouter piston 15a being integrally formed, which also helps to prevent loss of lubricating fluid from thechamber 70 in an outboard direction. - In some embodiments (not shown in the Figures), a manual rewind apparatus incorporating an elongate manual rewind shaft is provided, to rewind the
piston 15 back to its retracted position when it is necessary for the brake pads to be replaced, for example. In one example of a manual rewind apparatus, a piston engaging end piece is mounted on the manual rewind shaft, The end piece can be generally circular in profile, but with two diametrically opposed projections. The end piece and the projections are dimensioned such that the projections locate within thelongitudinally extending channels 42 of theinner piston 15b. Thechannels 42 allow theinner piston 15b to advance during a braking operation, whilst the shaft is axially fixed. - In use during manual adjustment, therefore, a user rotates the rewind shaft. Due to the engagement between the projections of the end piece and the
channels 42 of theinner piston 15b, theinner piston 15b is caused to rotate, rewinding thepiston 15 back to its original retracted position. - Preferably, the
longitudinal channels 42 are arranged to be located away from the opposing 'twelve o'clock' and 'six o'clock' circumferential locations on the radially inner surface of theinner piston 15b, for example at 'three o'clock' and 'nine o'clock', when the brake is assembled on an axle of a vehicle. Advantageously, this helps to further inhabit passage of lubricant through thechannels 42, which could occur under gravity through the most radially lower channel 42 (e.g. if a channel was at a 'six o'clock' position), when the brake is in a normal orientation. - The
chamber 70 comprises an opening at its inboard end, and loss of lubricating fluid in an inboard direction through the opening can be inhibited by a further sealing arrangement located at the inboard end within, or immediately adjacent, thechamber 70. In this embodiment, a sealing member can be provided atlocation 76, between the outboard-facing surface of thebearing 18a and the inboard-facing surface of theshoulder 40a of theyoke 20. A sealing member can also be provided atlocation 78, between the radially outer surface of thecollar 35a of thedrive drum 35 and the radially inner surface of theyoke 20. - Therefore, in use, a 'bath' of lubricating fluid is retained within the
chamber 70, i.e. substantially no lubricant can pass inboard of the inboard sealing arrangement through a potential fluid transmission path defined between theyoke 20 and thedrive drum 35. Similarly, no substantially no lubricant can pass outboard of the outboard sealing arrangement through a potential fluid transmission path defined between theinner piston 15b and theadjuster mechanism 30. The adjuster mechanism can be at least partially submerged in the 'bath' of the lubricating fluid. This reduces wear of the components of the adjuster mechanism, extending the life of a disc brake comprising this adjuster system. - The sealing members are preferably elastomeric o-rings, but it will be appreciated that any suitable sealing members could be used with minor modifications to the sealing arrangement that would be within the remit of the skilled person, e.g. lip seals, u-cups, metal sealing discs, etc.
- In alternative arrangements, the
chamber 70 is not fluid-tight, but simply configured to contain lubricant for lubrication of at least part of the wear adjustment mechanism, and inhibit lubricant from migrating away from the wear adjustment mechanism. As the lubricant is inhibited from escaping from a defined location, it is restricted from migrating to other areas of thedisc brake 2, reducing wear of the components of the adjustment mechanism, and extending the life of adisc brake 2 comprising this adjuster system. If the lubricant is grease or a lubricating oil, a higher quantity of lubricant can be maintained near the parts of the wear adjustment mechanism needing lubrication, such as the wrap spring and/or friction clutch plates. Thus, should there be a degradation or escape of the lubricant over time, a greater amount of lubricant will nevertheless remain in contact with the parts requiring lubrication. - One way to inhibit the lubricant is for the chamber and/or the wear adjustment mechanism to have a radial step arranged to define a barrier to inhibit the escape of lubricant in an inboard or outboard direction. For example, looking at
Figure 7 , thestop 44 of theinner piston 15b, which projects radially inwardly could be dimensioned and arranged to inhibit any lubricant contained outboard of thestop 44 from escaping in an inboard direction past thestop 44. Thewasher 45a could also be dimensioned to extend radially to a sufficient extent to overlap and perform the same function, i.e. inhibit lubricant from escaping. - As a disc brake is mounted in a fixed orientation on a vehicle, provision of a radial step tends to inhibit the escape of at least a portion of lubricant under gravity and may help to create a more tortuous path out of the chamber for lubricant in the event of lubricant being dislodged by virtue of the disc brake being subjected to vibration, jolts or the like. The radial step may advantageously extend around a complete circumference, such that a barrier exists irrespective of the orientation of the disc brake on a vehicle.
- The chamber and/or the wear adjustment mechanism may also have first and second opposed interface surfaces having a spacing sufficiently small therebetween so as to act a barrier to inhibit the escape of lubricant in an inboard or outboard direction. As an example, the
washers sleeve portion 40 of theyoke 20 could extend further in the outboard direction, such that its radially inner surface opposes the radially outer surface of theshoulder portion 37a of the drivendrum 37. - First and second opposed interface surfaces further improve the containment of lubricant within the chamber. The surfaces may be radially opposed or axially opposed. The spacing required may be larger for relatively viscous lubricants such as grease, and a closer fit for thinner.
- The
chamber 70 may be provided as a unitary item with the wear adjustment mechanism, such that removal of the adjustment mechanism from thecaliper housing 6 of thedisc brake 2 also results in removal of the chamber therefrom, for maintenance or replacement. - It will be appreciated that numerous changes may be made within the scope of the present invention. For example, certain aspects of the invention may be applicable to other types of brake, such as twin piston or electromechanically actuated brakes.
- In alternative embodiments, a different type of bearing arrangement could be utilised at the inboard end of the adjustment mechanism. For example, see
Figure 8 where an alternative arrangement is illustrated, with like reference numbers indicating like features, but with the prefix '1'. - In this alternative arrangement, the
drive drum 135 is restrained from moving in an outboard direction, and allowed to rotate relative to theyoke 120, by a first rolling element bearing 118a. Thefirst bearing 118a is an angular contact ball bearing. In this embodiment, an inner chamfer is arranged between a radially inner facing surface of thefirst bearing 118a and an inboard facing surface of thefirst bearing 118a. An outer chamfer is arranged between a radially outer facing surface of thefirst bearing 118a and an outboard facing surface of thefirst bearing 118a. - The inboard facing surface of the
bearing 118a engages an outboard facing surface of aflange portion 135c at the inboard end of thedrive drum 135. A surface inclined to the longitudinal axis of thedrive drum 135 is defined by the outer chamfer of thefirst bearing 118a and engages a corresponding inclined surface of theshoulder 140a of thesleeve portion 140 of theyoke 120. In this way, thedrive drum 35 is restrained from moving axially outboard, once the brake is assembled. As thefirst bearing 118a is an angular contact ball bearing, it will perform well under the axial loads that will be applied during operation of the brake. Thefirst bearing 118a also engages a radially outer surface of thecollar 135a of thedrive drum 135, to retain thedrive drum 135 in a radial direction, and to accept radial loads passing through thedrive drum 135. There is an axial clearance between thefirst bearing 118a and thewrap spring 139. As well as helping enable smooth rotation of thedrive drum 135 relative to theyoke 120, thefirst bearing 118a also helps to locate thedrive drum 135 radially, helping to prevent misalignment of thedrive drum 135 within the adjustment mechanism, which can impair adjuster function during the life of the brake. -
Figure 9 shows a further alternative arrangement, with like reference numbers indicating like features, but with the prefix '2'. In this embodiment, thesleeve portion 240 andyoke 220 are separate components that are not fixed together during assembly. Instead, in this embodiment, thesleeve portion 240 has an interference fit with theinner piston 215b. However, it will be understood that thesleeve portion 240 andinner piston 215b could be fixed together with any suitable arrangement that is within the knowledge of a person skilled in this field. - The
sleeve portion 240 has a reduced diameter portion at its inboard send that fits within the bore of theyoke 220. Thesleeve portion 240 can rotate relative to theyoke 220. The diameter of the bore of the yoke at thesleeve portion 240 is lower than the diameter of bore for the remainder of the yoke, such that aninternal shoulder 240a is defined between thesleeve portion 240 and the remainder of theyoke 220. - In this embodiment, there is no stop projecting radially inwardly from the
inner piston 215b. Instead, thesleeve portion 240 projects axially outboard to a greater extent than thesleeve portion 40 ofFigure 7 , such that it acts as a stop. Thesleeve portion 240 is radially outward of thecircumferential shoulder portion 237a that projects radially outwardly from the drivendrum 237 and seats one end of thewrap spring 239. In the axial direction, thewrap spring 239 is retained between thedrive drum collar 235a and awasher 245a, but does have some axial freedom of movement. There is again an axial clearance between the bearing 218a and thewrap spring 239. - When the
adjuster mechanism 230 is assembled, thesleeve portion 240 is located concentrically between thewrap spring 239 and theinner piston 215b. Thesleeve portion 240 rotates with theinner piston 215b because of the interference fit. Theinner piston 215b is configured to rotate during an adjustment operation, to cause thepiston 215 to advance. An outboard facing surface of theyoke 220 opposes and contacts an inboard facing surface of theinner piston 215b. Friction between these two surfaces helps to inhibit undesired vibration-induced torque from affecting the adjustment mechanism in operation, and causing undesired de-adjustment of the disc brake. Advantageously, the friction provides a consistent friction torque but in a small space envelope. - The two opposing surfaces are arranged to have sufficient friction to resist relative rotation of the
yoke 220 and theinner portion 215b of thepiston 215 with a torque greater than the torque required to cause the one-way clutch of the adjuster mechanism (in this case the wrap spring 239) to slip when the actuation force is released at the end of a braking operation. This helps to ensure that the one-way clutch slips rather than permits unwanted de-adjustment of the brake occurring during brake release. In this embodiment, the radially outward facing surface of the sleeve is hardened. In alternative embodiments, the radially inward facing surface of the rotatable portion is hardened. It has been found that by hardening one of the two engaging surfaces, undesirable fretting corrosion can be significantly reduced. - The
wear adjuster mechanism 230 comprises first andsecond washers first washer 245a is located adjacent and inboard of thefriction clutch 241, and engages the friction clutch, as well as an outboard facing surface of thesleeve portion 240. Thesecond washer 245b is located adjacent and outboard of thefriction clutch 241, and an inboard surface of thewasher 245b engages thefriction clutch 241. An outboard face of thesecond washer 245b is acted on by thecompression spring 247. Thecompression spring 247 is, in this embodiment, arranged concentrically within theinner piston 215b, between thesecond washer 245b and thesecond bearing 218b to load thefriction clutch 241. - The
compression spring 247 is pre-stressed by thesecond bearing 218b. The second rolling element bearing 218b is provided between a radially outer surface of the projectingportion 235b of thedrive drum 235 and a radially inner surface of theinner piston 215b. In this embodiment the second rolling element bearing 218b is identical to the first rolling element bearing 218a, also being a deep-groove ball bearing, but is larger as it must fit between thedrive drum 235 andinner piston 215b. Thebearing 218b has radially arranged inner and outer races. Thebearing 218b is axially fixed relative to the projectingportion 235b. Thebearing 218b can slide relative to theinner piston 215b. In this embodiment, thebearing 218b is axially fixed relative to the projectingportion 235b by the inner race being an interference fit with the projectingportion 235b. Thecompression spring 247 is compressed by and supported directly on the outer race and is therefore isolated from rotation of the projectingportion 235b, but applies a force to thedrive drum 235 as a whole in an outboard direction because of the interference fit between thesecond bearing 218b and the projectingportion 235b of thedrive drum 235. There is also a load path from thecompression spring 247 through thefirst washer 245a to thesleeve portion 240 to urge thesleeve portion 240 in the inboard direction. Due to the interference fit between thesleeve portion 240 and theinner piston 215b, theinner piston 215b is also urged in the inboard direction, towards theyoke 220. This helps to control the friction between the opposing surfaces of theyoke 220 andinner piston 215b and resist relative rotation of the two components, without the need for an inner piston stop, as required in previous embodiments. The axial location of thesecond bearing 218b is carefully controlled during assembly to apply an appropriate pre-load to thecompression spring 247. - The arrangement of the
second bearing 218b also further assists with radial alignment in an angular sense (i.e. the drive drum, the yoke and the inner piston and inner piston remain co-axial) under eccentric loads from the operating shaft during an adjustment operation, and in particular during the return of the operating shaft and piston to their brakes-off rest positions. The axial load from the compression spring 247 (of the order of 600N) is transmitted to thedrive drum 235 and then into theyoke 220 by thefirst bearing 218a.
Claims (15)
- An actuation mechanism for a disc brake (2), the actuation mechanism comprising:a non-rotatable yoke (20) to transmit an actuating force from an operating shaft (21);a piston (15) configured to be driven by the yoke (20) to transmit the actuating force to a brake pad (11a, 11b), the piston (15) comprising a portion rotatable with respect to the yoke (20) to cause the piston (15) to extend; anda wear adjustment mechanism (30) for adjusting extension of the piston (15) to account for wear of the brake pad (11a, 11b), the wear adjustment mechanism (30) including a driving portion configured to be driven by the operating shaft (21), to transfer torque from the operating shaft (21) to the rotatable portion of the piston (15) to cause the rotatable portion to rotate and extend the piston (15), characterized in that the driving portion is a drive drum (35) that is directly engaged by a link member that is connected to, or integral with, the operating shaft (21),wherein a rolling element bearing (18a, 18b) is located between the driving portion of the wear adjustment mechanism (30) and the yoke (20).
- The actuation mechanism of claim 1, wherein the yoke (20) comprises a generally inboard facing surface that opposes a generally outboard facing surface of the driving portion to define an annulus that locates the rolling element bearing (18a, 18b).
- The actuation mechanism of claim 1 or claim 2, wherein the rolling element bearing (18a, 18b) is a deep-groove ball bearing.
- The actuation mechanism of claim 1 or claim 2, wherein the yoke (20) comprises an inclined surface and the rolling element bearing (18a, 18b) is an angular contact ball bearing with a corresponding inclined surface to engage the inclined surface of the yoke (20).
- The actuation mechanism of any previous claim, wherein an inboard facing surface of the rotatable portion of the piston (15) engages an opposing outboard facing surface of the yoke (20) such that friction is created between the inboard facing surface of the rotatable portion of the piston (15) and the opposing outboard facing surface of the yoke (20), to resist relative rotation of the yoke (20) and the rotatable portion of the piston (15).
- The actuation mechanism of claim 5, wherein a resilient element is arranged to provide a load acting to urge the facing surfaces of the yoke (20) and the piston (15) into contact.
- The actuation mechanism of claim 5 or claim 6, wherein the driving portion is part of a one-way clutch, the one-way clutch further comprising a driven portion, preferably wherein rotation of the yoke (20) in relation to the rotatable portion of the piston (15) is frictionally resisted with a torque greater than the torque required to cause the one-way clutch to slip, when the actuation force is released at the end of a braking operation.
- The actuation mechanism of claim 7, wherein one of the driven or driving portions of the one-way clutch comprises an axially extending projecting portion (35b), and optionally the other of the driven or driving portions is rotatably mounted with respect to the projecting portion (35b).
- The actuation mechanism of claim 8, wherein the resilient element is arranged to apply a load to the projecting portion (35b), the load being transmitted to the yoke (20) via the rolling element bearing (18a, 18b).
- The actuation mechanism of claim 9, wherein the resilient element is further arranged to apply a load to a torque limiting clutch of the wear adjustment mechanism (30).
- The actuation mechanism of claim 9 or claim 10, wherein the resilient element is further arranged to apply a load to the piston (15) in an opposite direction to the load on the yoke (20).
- The actuation mechanism of claim 11 wherein the wear adjustment mechanism (30) further comprises a second rolling element bearing (18a, 18b) mounted at an outboard end of the projecting portion (35b) to take the load from the resilient element, preferably wherein the axial location of the second rolling element bearing (18a, 18b) determines the amount of load applied by the resilient element.
- The actuation mechanism of claim 12 wherein the second rolling element bearing (18a, 18b) is axially fixed relative to the projecting portion (35b) and located on a force transmission path between the resilient element and the projecting portion (35b), preferably wherein the first and second rolling element bearings (18a, 18b) are substantially identical.
- A method of assembling a disc brake (2) comprising the steps of:
installing an actuation mechanism within the disc brake (2), the actuation mechanism comprising:a non-rotatable yoke (20) to transmit an actuating force from an operating shaft (21);a piston (15) configured to be driven by the yoke (20) to transmit the actuating force to a brake pad (11a, 11b), the piston (15) comprising a portion rotatable with respect to the yoke (20) to cause the piston (15) to extend; anda wear adjustment mechanism (30) for adjusting extension of the piston (15) to account for wear of the brake pad (11a, 11b), the wear adjustment mechanism (30) including a driving portion configured to be driven by the operating shaft (21), to transfer force from the operating shaft (21) to the rotatable portion of the piston (15) to cause the rotatable portion to rotate and extend the piston (15), wherein the driving portion is a drive drum (35) that is directly engaged by a link member that is connected to, or integral with, the operating shaft (21),wherein the method comprises the step of locating a rolling element bearing(18a, 18b) between the driving portion of the wear adjustment mechanism (30) and the yoke (20). - A disc brake (2) comprising the actuation mechanism of any of claims 1 to 13.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP18170189.7A EP3564549A1 (en) | 2018-04-30 | 2018-04-30 | A disc brake |
Publications (2)
Publication Number | Publication Date |
---|---|
EP3581448A1 EP3581448A1 (en) | 2019-12-18 |
EP3581448B1 true EP3581448B1 (en) | 2023-03-01 |
Family
ID=62091789
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP18170189.7A Withdrawn EP3564549A1 (en) | 2017-07-21 | 2018-04-30 | A disc brake |
EP19169827.3A Active EP3581448B1 (en) | 2018-04-30 | 2019-04-17 | A disc brake |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP18170189.7A Withdrawn EP3564549A1 (en) | 2017-07-21 | 2018-04-30 | A disc brake |
Country Status (3)
Country | Link |
---|---|
US (1) | US11261928B2 (en) |
EP (2) | EP3564549A1 (en) |
CN (1) | CN110410435B (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3564549A1 (en) * | 2018-04-30 | 2019-11-06 | Meritor Heavy Vehicle Braking Systems (UK) Limited | A disc brake |
EP3431799B1 (en) * | 2017-07-21 | 2022-05-25 | Meritor Heavy Vehicle Braking Systems (UK) Limited | A disc brake |
EP3564553B1 (en) * | 2018-04-30 | 2022-06-08 | Meritor Heavy Vehicle Braking Systems (UK) Limited | An adjuster mechanism |
US11608045B2 (en) | 2020-09-16 | 2023-03-21 | Arvinmeritor Technology, Llc | System and method of checking sealing of a brake caliper housing |
US11821482B2 (en) | 2020-09-18 | 2023-11-21 | Arvinmeritor Technology, Llc | Brake assembly and method of adjustment |
US11718283B2 (en) | 2020-09-18 | 2023-08-08 | Arvinmeritor Technology, Llc | Brake assembly having a sensor |
CN113410942B (en) * | 2021-07-28 | 2024-06-07 | 河南全新机电设备有限公司 | Damping wheel type bearing device between stator and rotor of direct-driven motor of mill |
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DE4032885A1 (en) * | 1990-10-17 | 1992-04-23 | Knorr Bremse Ag | DISC BRAKE FOR VEHICLES, IN PARTICULAR ROAD VEHICLES |
DE4121054A1 (en) * | 1991-06-26 | 1993-01-07 | Teves Gmbh Alfred | PRESSURE-CONTROLLED ADJUSTMENT FOR A VEHICLE BRAKE |
SE505339C2 (en) * | 1994-10-24 | 1997-08-11 | Haldex Ab | Disc brake caliper |
GB9526019D0 (en) | 1995-12-20 | 1996-02-21 | Lucas Ind Plc | Improvements relating to disc brake construction |
JPH11287267A (en) | 1998-03-31 | 1999-10-19 | Tokico Ltd | Disc brake |
US6374958B1 (en) | 1999-03-31 | 2002-04-23 | Tokico Ltd. | Motor-driven disk brake |
NL1013651C2 (en) | 1999-11-23 | 2001-05-28 | Skf Eng & Res Centre Bv | Actuator with compensation of alignment differences. |
SE516496C2 (en) * | 2000-04-03 | 2002-01-22 | Haldex Brake Prod Ab | The brake mechanism |
US6394248B1 (en) * | 2000-05-31 | 2002-05-28 | Ntn Corporation | Compression spring complaint one-way over-running clutch pulley |
ATE388344T1 (en) | 2000-08-17 | 2008-03-15 | Knorr Bremse Systeme | DISC BRAKE WITH AN ADJUSTER ON EACH SIDE OF THE BRAKE DISC |
EP1576303A1 (en) * | 2002-12-23 | 2005-09-21 | Haldex Brake Products AB | Brake gear for a disc brake |
CN1661257A (en) * | 2004-02-28 | 2005-08-31 | 陈坤 | High safety disk brake and clutch |
EP2476929B2 (en) | 2008-08-14 | 2016-08-03 | WABCO Europe BVBA | Adjustment device for a disc brake |
DE102010011725A1 (en) * | 2010-03-17 | 2011-09-22 | Haldex Brake Products Ab | Disc brake and method of manufacturing a disc brake |
EP2971838B1 (en) * | 2013-03-11 | 2017-05-10 | Haldex Brake Products AB | Disc brake, brake actuation mechanism for such a disc brake and method for brake adjustment |
CN103727154A (en) | 2014-01-14 | 2014-04-16 | 安思通(厦门)制动系统有限公司 | Integrated parking braking device |
DE202014002459U1 (en) * | 2014-03-19 | 2014-04-17 | Haldex Brake Products Ab | Disc brake and brake actuation mechanism for a disc brake |
DE102014111545B4 (en) * | 2014-08-13 | 2021-08-19 | Knorr-Bremse Systeme für Nutzfahrzeuge GmbH | Application device of a rotary lever-operated disc brake |
EP3051169A1 (en) | 2015-01-28 | 2016-08-03 | Meritor Heavy Vehicle Braking Systems (UK) Limited | A disc brake |
EP3564549A1 (en) * | 2018-04-30 | 2019-11-06 | Meritor Heavy Vehicle Braking Systems (UK) Limited | A disc brake |
EP3431799B1 (en) * | 2017-07-21 | 2022-05-25 | Meritor Heavy Vehicle Braking Systems (UK) Limited | A disc brake |
EP3450788B1 (en) * | 2017-08-31 | 2020-10-21 | Meritor Heavy Vehicle Braking Systems (UK) Limited | A disc brake |
-
2018
- 2018-04-30 EP EP18170189.7A patent/EP3564549A1/en not_active Withdrawn
-
2019
- 2019-04-05 US US16/376,012 patent/US11261928B2/en active Active
- 2019-04-17 EP EP19169827.3A patent/EP3581448B1/en active Active
- 2019-04-28 CN CN201910348212.1A patent/CN110410435B/en active Active
Also Published As
Publication number | Publication date |
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CN110410435B (en) | 2021-08-10 |
EP3564549A1 (en) | 2019-11-06 |
BR102019008646A2 (en) | 2020-01-07 |
US11261928B2 (en) | 2022-03-01 |
US20190331184A1 (en) | 2019-10-31 |
CN110410435A (en) | 2019-11-05 |
EP3581448A1 (en) | 2019-12-18 |
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